What Is FIP in Baseball? Fielding Independent Pitching

FIP in baseball is fielding independent pitching: a stat that grades a pitcher using only the three outcomes they control almost entirely — strikeouts, walks (with hit-by-pitches), and home runs — and ignores everything that depends on the defense behind them. It is then scaled to resemble ERA, so a FIP of 3.20 reads just like an ERA of 3.20. The idea is to strip out the fielders, the luck on balls in play, and the sequencing, and leave a cleaner picture of the pitcher alone.

That matters because ERA blames a pitcher for runs that are partly the defense’s doing. Two pitchers can throw identically and post different ERAs simply because one had better fielders or luckier bounces. FIP tries to remove that noise.

The formula

FIP weights the three controllable outcomes, divides by innings, and adds a constant:

FIP = ((13 × HR) + (3 × (BB + HBP)) − (2 × K)) ÷ IP + constant

• HR = home runs allowed
• BB = walks, HBP = hit by pitch
• K = strikeouts
• IP = innings pitched
• constant = a league-adjustment figure, typically around 3.10 (it is recalculated every season, so treat that as approximate rather than fixed)

The weights reflect run value: a home run does the most damage, walks a moderate amount, and strikeouts help the pitcher, which is why they carry a negative sign. The constant does one job — it shifts the whole scale so league-average FIP lines up with league-average ERA.

A worked example

Take a starter with these season totals: 20 home runs, 55 walks, 5 hit-by-pitches, 210 strikeouts, over 200 innings. Using a constant of 3.10:

• Home runs: 13 × 20 = 260
• Walks and HBP: 3 × (55 + 5) = 180
• Strikeouts: 2 × 210 = 420
• Numerator: 260 + 180 − 420 = 20
• Divide by innings: 20 ÷ 200 = 0.10
• Add the constant: 0.10 + 3.10 = 3.20

A 3.20 FIP is a strong, above-average season. The heavy strikeout total is doing the work here — it drags the numerator down and keeps the final figure low even with 20 home runs allowed.

How to read FIP

Because FIP is scaled to ERA, the tiers look familiar.

FIP	Rating
Below 3.00	Excellent, ace-level
3.00 to 3.75	Above average to good
3.75 to 4.20	Roughly league average
4.20 to 5.00	Below average
Above 5.00	Poor

The most useful trick with FIP is comparing it to ERA. When a pitcher’s ERA sits well below their FIP, they have likely gotten help from their defense or some good fortune on balls in play, and their runs allowed may climb toward the FIP going forward. When ERA sits well above FIP, the pitcher has probably been unlucky and could improve. That gap is one of the first things analysts check when they suspect a hot or cold streak will not hold.

Why FIP matters, and its limits

FIP is a better predictor of future ERA than past ERA is, which is its main selling point — it captures the skill under the results. But it is not a complete verdict. It assumes a pitcher has no meaningful control over the quality of contact on balls in play, and some pitchers, through movement or deception, genuinely suppress hard contact in ways FIP misses. Its cousin xFIP goes a step further and normalizes home runs, trading realism for stability.

For the traditional runs-allowed view this is built to improve on, see our explainer on ERA in baseball. FIP pairs naturally with WHIP, which tracks baserunners allowed, and with BABIP, the batted-ball-luck stat that often explains an ERA–FIP gap. For a pitcher’s total value in one figure, WAR uses FIP-style inputs on the pitching side.

If you are weighing an arm for a fantasy staff, our fantasy baseball trade analyzer leans on skills-based stats like these rather than surface ERA, so you are buying the pitcher, not the defense behind him.

In short: FIP is the ERA-scaled stat built only from strikeouts, walks, and home runs, its constant sits near 3.10, and reading it against ERA tells you whether a pitcher has been lucky or good.